Focusing device for cameras.



'euarrnn srarss PATENT oirrron.

SGEN W'GODEURY, NRCESTEBL, VVtSSACHUSETTS.

Fbi

1,1 6&032.

Application. led September 5, i913.

To (/Z 'if/hom il may confiere.'

lle it lrnown that .fioinv FJ. lVooonUnY, a citizen of the llnited States, residing; at livorcester, in the countyv of ll'vorcester and State of Massachusetts.y have invented a new and useful Focusing Device for Cameras, of which the following` is a specification.

This invention relates to a device for ascertaining when a camera is in focus, and the principal objects thereof are to provide a device of this character which can oe set in accurate position at the factory so that it will operate accurately at certain distances and with small variations at intermediate distances; to provide a construction for this purpose lin which the parts are of such a nature that the)7 can he made h v simple and inexpensive processes and that they will talle up comparatively little room on the camera and will not interfere with the folding of the parts in the case.

Further objects and advantages of the invention will appear hereinafter.

Reference is to he had to the accompanying drawings in which. l

Figure l is a front elevation of a camera of well known type showing a preferred embodiment of this invention applied. thereto; Fig.l 2 is a plan of the same; Fig. 3 is a side view of the attachment; Fig'. 'el is a plan of the lower member thereof; Fig. 5 is a diagrammatic side view showing the device set for infinite distances and showing the die rection of a li ght ray coming from an object in focus. Fig. 6 is a similar view showingthe instrument adjusted slightly out of focus and indicating the course of a ray from infinite distance. Fig. 7 is a, plan showing the ilnagevohserved in Fig. when in focus. Fig). 8 is a similar view showing the appearance of the image not in focus, as in Fig. 6, and F 9 is a view similar to Fig. 5 with the device' set for focusing" on an ohiectat a .short distance.

For the purposer of amzomplishing; the above named objects l provide means (preferahlv an inclined mi rror) for directing rays of light coming from the objecton which the camerais being focused to a position for observation, as for exampleJ a reducingA glass. At a distance from it l provide a second means (preferably a parallel mirror) for directing other rays from the same ohject to said reducing' glass, so that normally the two images will he in registration. To permit observation of both images the `first Spceicatcn of 'Letters Patent.

yatented Der. 23, H 5.

Serial No. 788.3%.

mirror may have a transparent spot. ln order that the second image ma;r he thrown out of registration with the first when the camera is not in focus, l. provide means.y adjustable with the camera lens, for equally delieeting all the rays coming" from the second means or mirror to the lirst. This means is so made and set that when an object at a given distance is in focus the amount of deflection will he OC. ln other words the focal length of this means` which is a lens, is coordinated with the focallength of the carriera lens and the length of the triangulation hase, that is the distance between the inclined mirrors or other reliectine: devices. rEhe relative adjustment of this lens and the camera lens provides for using1 dilferent portions of the lens for observing the reflection of the object in one of the mirrors and the consequent deflection to di tferent degrees of the rays passing;r through it according' to its relative position. Thus the two images will register when the camera is in focus. By adjustment of the camera lens and deliecting device in either direction. however, a slight deflection will occur, which will be observed through the reducing glass as lack of registration h'v the two images.

The attachment is shown as applied to a camera of well known construction comprising a lens holder l() which is adapted to he adjusted forward and hack` in the well lznown way. In the form of the invention shown7 the attachment consists of two members, one of which is attached to and Ymoves with the lens 1l of the camera. purpose this part of the attachment is shown as comprisingr a frame having spaced side 'walls l2. One of .these side walls is shown as perforated for the admission of the edge of the holding' plate of the camera.

At a point near the top. an inclined mirror i3 (the iirst directing means above mentioned) is shown having a portion which is not silvered on the hack. T his is shown as a rectangular opening le. Ahove/ this mirror is a horizontal. double concave reducing lens 15. This mirror and lens are shown as formed on an inner frame 1G consisting of metal land adapted to he adjusted on the inair. frame and secured in adjusted position by .fr screw and nut i7.

Wear the bottom the main frame is provided with another metal frame 1S Set iUlO i' and having a horizontal negative, preferahljv a double concave, lens 19 hired therein.

For this The outer side wall 12 is cut away below this mirror, and at a point still lower there is a second directing means in the form of an inclined mirror 20. The two reflecting devices 13and 20 are located substantially in parallelism but for practical purposes they are made to converge downward very slightly. The mirror 13 is at a forty-live degree angle to the horizontal and the mir.

.The other portion yof the attachmentcomprises a frame 25 mounted on the bottom plate of the camera and preferably made adjustable thereon,both horizontally and laterally so that it can be fixed in proper position l at the factory and secured there before it is shipped. At the top of this frame, which yeXtends upwardly at the side, is pivoted a A frame 26 to which is secured a lens 27. The

lens 27 is a positive, preferably a double con- Vex spherical, lens of the same focal length as the lens 19.

The frame 26 is adapted to swing up into position and pass through a slot 21 below the lens 19 so that as the camera lens is moved out and in the lens 19 will move to differentpositions over the lens 27. The two lenses 19 and 27 constitute the deflecting means above mentioned.

The use and function of the device will be best seen with reference to Figs. 5, 6, 7 and 8. in Fig. 5 the parts are shown in the position in which light rays'from a great (in finite) distance fall upon the two mirrors at such an angle that in the position shown, the horizontal rays falling on the mirror 13 are reiiected directly through the lens 15 in a vertical direction, while the horizontal rays falling on the mirror 20 are reflected upwardly, rearwardly to a slight extent, and then are deflected iirst in one direction and then in the other by passing through the two complementary lenses 27 and 19. Consequently, the images from the two rays indicated in Fig. 5 as seen through the lens 15, will be in registration. In other words, a horizontal line as seen at a distance with the parts shifted until the camera is in focus will form a` continuous unbroken image through the glass 15 as shown in F ig. 7.

`l3nt if the object being observed is not in focus, then the image on the silvered part of the mirror 13 will showthe horizontal line in .one position, whereas the image seen through the unsilvered part will show the horizontal line in another position as indicated in Figs. 6 and 8.

Fig. 9 Shows the direction of the light at hand but not in focus.

. aisance rays and position of the parts when the camera is focused on a near object. ln this case, the upper light ray acts in the same way as before and the lower light ray is reiiected at a sharper angle and then deflected through the two lenses so that its image coincides with the` image of the upper'ray. The dot and dark lines in this case show the course of a ray of light from an object near 1t will be seen that by selecting the proper curvatures of the lenses 27 and 19 and having their focal lengths the same, parallel rays passing through both of them at an inclination from below the lower one will be deflected iirst in one direction and then in the othersand will emerge upwardly from the lens 19 parallel with each other as would be the case if they had passed through a plane prism. By the vertical adjustment of the mirror 13, variations in the local lengths of commercial lenses, including the camera lens, can be compensated for, and the device can be set so that the two points at which the greatest accuracy is obtained can be at any desired distance from the camera, within certain limits.

Another advantage of this invention lies in the fact that the inclination of the two mirrors 13 and 20 are relatively fixed. Thus there is no diiculty due to the well known fact that a changein the angular relation between them would result in a change in direction of the reiiected rays equal to twice the angle through which one of the mirrors turned. Furthermore, the deflection of the light is controlled bymeans that is purely optical, instead of part optical and part mechanical.

Although l have illustra-ted and described only one embodiment ofthe invention and shown it as applied to a camera of one type only, I am aware of the fact that it is capable of general application and can be made inmany other ways without departing from the scope of the invention as expressed in the claims. Therefore. l do not wish to be limited in these respects, but y What l do claim is 1. The combination, in a focusing device for a camera having an adjustable lens, of means for directing rays of light from a given line into position to enable the operator to observe said line, a second means, at a distance from the first means, for normally directing rays of light from the same line into the same position, both of said means being movable together with the lens, and means between said first and second means for delecting the last named rays from said position when the camera. is not in focus on said line.

2. rlhe combination, in a focusing device for a camera having an adjustable lens, of means for directing rays of light from a given horizontal line into position to enable the operator to observe said line, a second means, relatively fixed at a distance vertically from the first means, and movable therewith and with the lens for normally directing rays of light from the same line into the saine position, and independcnf' means for defiecting the last named rays vertically from said position when the camera is not in focus on said line.

3. The combination in a focusing device for a camera, of meansy for directing rays of light from a given line into position to enable the operator to observe said line, a second means in fixed angular relation to the first means for normally directing rays of light from the same line into the same position, and independent means for deflecting the last named rays from said position when the camera is not in focus on said line, said independent means and ray directing means being relatively movable.

Ll. he combination, in a focusing device for camera, of a pair of reflecting devices both having a, fixed inclination, means for observing rays of liglit reflected from both reflecting devices by the same object in two adjacent fields, and means between one of said reflecting devices and the first named means for deflecting rays of light coming from an ob'ect not in focus to a position in which they will be observed out of registrationy with the rays of light coming from the same object and reflected by the other reflecting device.

5. The combination, in a focusing device for a. camera, of a pair of inclined reflecting devices, areducing glass positioned for observing rays of light reflected from both reflecting devices by the same object, and

means located between one of said reflecting devices and the reducing glass for deflectrays of light coming from an object not in focus to a position in which they will be observed through the reducing glass out of 1egistration with the rays of light coming from the same object and reflected by the other reflecting device.

(i, The combination, in a focusing device for a camera, of a pair of inclined reflecting devices, a reducing glass positioned for observing rays of light reflected .from botl refiecting devices by the same object, and means located between one of said reflecting devices and the reducing glass, and relatively adjustable as the camera lens moves, for deflecting rays of light coming from an object not in focus to a. position in which they will be observed through the reducing glass out of registration with the rays' of Alight coming from the same object and relilected by the other reflecting device. f

7J in a. device of the character described, .he combination of nearly a pair of parallel mirrors, one having an unsilvered transparent portion near the center thereof, and adjustable means for equally deflecting all rays of light reflected from the other mirror toward said transparent portion.

8. 1n a device of the character described, the combination of nearly a pair of substantially parallel inclined mirrors located one above the other, the upper one of said mirrors having an unsilvered transparent portion whereby a ray of light coming from a certain direction on the lower mirror will normally be reflected through said transparent portion, and. a ray of light from the same point will be reflectedfrom a point at the same height on the upper mirror, and adjustable means between said deflecting the rays of light passing the lower mirror.

9. In a focusing device for a camera, the combination of two lenses, one a positive lens and the other a negative lens, of substantially the same focal length, one of said lenses being movable in its own plane adjacent to the other, and means connected with said lenses for directing the rays of light through them in adjusted positions and for registering said rays coming from the object to be observed without passing through said lenses.

10. 1n a device of the character described, the combination of a pair of inclined mirrors, one located over the other and both fixed substantially at an incline of fortyfive degrees to the horizontal, the upper mirror having an unsilvered transparent portion., and adjustable means for deflecting -a ray of light reflected from the lower mirror through said transparent portion, said adjustable means comprising a negative lens in stationary position with respect to said mirrors and a positive lenf of the same focal length and located adjacent to the double concave lens, one of said lenses being movable in its own plane for adjustment.

ll. 1n a focusing device, the combination of a pair of reflecting devices substantially parallel with each other, a reducing glass in position for simultaneously observing` an object by reflection from both reflecting devices, and a pair of lenses located between one of said reflecting devices and the reducing glass, 4one a concave lens and the other a convex lens, both having the same focal length, and means whereby one of said lenses can be adjusted along theother for varying the deflection of a ray of light refrom flected from the mirror beyond the lenses to said reducing glass.

l2. The combination in a focusing device for a camera having a lens movable for focusing purposes, of a pair ofreficcting devices inclined and substantially parallel with each other, a glass through which light reflected from both reflecting devices can be mirrors for f rays of light with.

fields, a double concave lens between one of said reflecting devices'and said glass, both of said lenses and reflectil' devices being movable with the camera lens, and a double convex lens havingthe same focal length as said double concave lens-in fixed position with respect to the position of the negative in the camera and parallel with said double concave lens, whereby as the camera lens is moved back and forth, the relative positions of the double concave and double convex lenses will be adjusted with it.

13. The combination, in a focusing device for a camera, of a reducing glass, a pair of inclined reflecting devices, means located between one of said reflecting devices and the reducing glass, and relatively adjustable as the camera lens moves, for deflecting rays of light coming from an object not in focus to a position in which they will be observed out of "registration with the rays of light coming from the same object vand reflected by the other reflecting device, and means for adjusting the distance between said refleeting devices.

14. The combination, inl al'focusing device, of two reflecting devices having'a fixed inclination but adjustable toward and from each other to compensate for inaccuracies and to permit adjustment of the distance of the points of greatest accuracy invfocusing, and means between the reflecting devices for deflecting the rays of light reflected from one reflecting device toward the other relecting device.

15. T lie-combination in a focusing device for a camera, of means for normally directingv two separated rays of light lfrom the same positions for observapoint into registering and means independtion vby the operator,

ent thereof for deflecting one of said rays.

of light, said directing and deflecting'means being relatively movable to cause the deflection of one of the rays from the normalposition when the camera is not in focus.

16. In a photographic focusing device, the combination with a camera embodying asupporting structure for the sensitive material and a lens structure, said structures being movable relatively to each other to focus the camera lens, of a pair of substantially parallel relatively fixed mirrors carried by one of said structures and means carried by the other of said structures for deflecting a ray reflected by one mirror into or out of parallelism with a ray reflected by the other mirror accordingly as the camera lens is 1n or out of focus with respect to an from which both rays emanate. j

17. In a photographic focusing device, the

obj ect Acombination with a camera embodying a supporting structure for the sensitive materml,

and a lens structure, said structures being lmovable relatively to each other to focus .movable in parallelism as the structures are moved relatively.

18. In a photographic focusing device,the combination' with a camera comprising a support for the sensitive material and a lens carriage movable relatively thereto to focus the camera lens, of a pair of substantially parallel relatively fixed mirrors carried by the carriage and a deflecting lens fixed to the support for deflecting a ray reflected by one mirror into or out of parallelism with a ray reflected bythe other mirror accordingly as the camera lens is in or out of focus with respect to an object from which both rays emanate, the said deflecting lens being arranged in a plane transverse to the path of a ray and parallel to the direction of move` ment as the lens carriage and mirrors are shifted.

19. In a photographic focusing device, the combination with a camera embodying a supporting structure for the sensitive mateparallel relatively fixed mirrors carried by one of said structures to jointly reflect the image of an object, and a positive and a negative lens of the same focal length and having parallel axes that arealso parallel to said image rays reflected from one mirror, said lenses being relatively movable transversely of the path of said rays j yroportionately to the relative movements of the two first mentioned structures to vary the relationship of their axes. j

20. In a focusing device, the combination with the camera lens, of two parallel separated mirrors and a second lens in posi tion for receiving rays reflected by one of the mirrors j and coming from the object on which the camera is being focused, the focal length of which second lens is coordinated with the focal length of the camera lens and the length of the triangulation base, and'means whereby a relative rectilinear motion is produced between the second lens and the mirrors as the camera lens is moved for focusing, whereby different portions of the second lens are used for observing the reflection to said object in one mirror and rays so reflected are deflected to different degrees on )assinff throufrh said second lens accordin 21. In a focusing device, the combination with the camera lens, of two parallel separated mirrors and a second lens in position for receiving rays reflected by one of the mirrors and coming from the object on which the camera vis being focused, the focal length of which second lens is cordinated with the focal length of the camera lens and the distance between the mirrors,

said mirrors being perrl Lnently located substantially at l5@ to the plane of the second and coming from the object on which the camera is being focused, the second lens and the mirrors being relatively movable in the direction in which the camera lens is moved for focusing, whereby different portions of the second lens are used for observing the reflection of said object in one mirror and rays so refiected are deflected to different degrees on passing through said second lens according to the different relative positions of the second lens and vmirrors for the purpose of bringing them into registration with the corresponding rays reflected by the other mirror.

In testimony whereof I have hereunto set my hand, in the presence of two subscribing witnesses.

, JOHN E. VVOODBURY. W'itnesses:

ALBERT E. FAY, C. FoRREs'r Wessonu Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

Corrections In LettersA Patent No. 1,166,032.

lt is hereby certified that inA Letters Patent No. 1,166,032, granted December 28, 1915, upon the application of John Woodbury, of Worcester, Massachusetts, for an improvement in ,Focusing Devices for Cameras, errors appear in the printed specification requiring correction as follows: Page 2, line 86, for the Word local read focal; page 3, lines 64 and 71,claims 7 and 8, strike out the Word nearly, and same page, lines, and claims, before the Word parallel insert the Word nearly; and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the'case in the PatentOiice.

Signed and sealed this 30th day of May, A. VID., 1916.

, J. T. NEWTON, Acting Commissioner of Patents. 

